Very little was expected from Chancellor Angela Merkel’s latest visit. But putting that aside, there have to be major doubts that any renegotiation of the terms of the UK’s EU membership would amount to much, however badly some of us would like to see it.

But these are radical reforms, requiring a radical change of mindset for the EU, which accretes power rather than disperses it. For those expecting to see them achieved, I quote Merkel’s speech from February 2014: “I am afraid they are in for a disappointment.”

Christopher Howarth is senior policy analyst at Open Europe, says No

Barring a diplomatic meltdown, Cameron will be able to claim success in renegotiating the UK’s EU membership terms. However, cynics may observe that the chances of producing ersatz success are limitless. If Cameron tailors his “demands” to what Germany is willing to allow, and then marks his own homework, it could produce a strong impression.

But there’s no need for cynicism: EU reform is possible, and Cameron is right to see Merkel as key. Germany has reasons to avoid a UK exit, in terms of trade, geopolitical clout, and because Berlin could end up stuck in an EU dominated by protectionist free spending states. So if he asks for modest and reasonable new terms, he should get a fair hearing.

Both leaders know that they need to do more than create an illusion. The degree of EU reform achieved will be a key factor in the 2017 EU referendum. And with trust in politicians at an all-time low, anything short of real fundamental reform could risk a UK exit.